Process for rust-proofing iron and steel.



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WAIJTER I. OESCHGER, OF DETROIT, MICHIGAN, ASSIGNOR T PARKER RUST PROOFCOMPANY OF AMERICA, 0F DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

PROCESS FOR RUST-PROOFING IRON AND STEEL.

To all whom it may concern."

Be it known that. I, ,WALTER I. Onscnqnn, a. citizen of the UnitedStates and residing at Detroit, in the county of Wayne and State ofMichigan, have invented a new and Improved Process for Rust-ProofingIron and Steel, of which the following 1s a specification. Y

This invention relates to a process for forming rust-proof surfaces onarticles of iron and steel or alloysthereof, and its ob ject is toprovide a process whereby the articles to be treated are subjected tofumes or Vapors which produce surfaces of basic ferro-ferric phosphatesof iron which are heavy and very dense.

This invention consists in subjecting the surfaces of the articles ofiron and steel to be treated to fumes or vapors produced by highlyheating metallic phosphates such as the acid meta-phosphates oftungsten, molybdenum or of any of the metals of the third, fourth andfifth groups, according to the analytical classification (set forth byProf. G. S. Newth, T. (3., F. G. 8., in the eighth edition of his Manualof 07101126- cal Analysis, published by Longmans, Green & Co, New York,in 1909), either singly or in combination with each other.

In this classification, tungsten is in the first group, molybdenum inthe second group, while the third, fourth and fifth groups includealuminum, chromium, co balt, iron, nickel, manganese, zinc, barium,strontium, calcium. sodium, potassium, magnesium and vanadium.

The acid meta-phosphate of most general application is made by placing aquantity of iron oxid, preferably powdered black iron scale, (Fe,0 in apot with suflieient phosphoric acid to form a soft paste. A quantity ofWater about equal in amount to the acid may be added to keep the massfrom caking, after which heat is applied and the material is stirreduntil a dry granular mass is obtained, which is then'powdered. The

Specification of Letters Patent.

Patented Jan. 22, 193%..

Application filed February 21, 1917. Serial No. 150,016..

The reactions may be expressed as follows: When heated Fe,o,+sumo;ereroemrogamo.

And continued heating results in driving of the water of combinationzrero en ro 2Fe(PO ,2HPO +8H,0.

This is an acid meta-phosphate.

Carbonates and oxids of theother metals may be similarly treated. Caremust be taken to avoid heating these phosphates to a point where thereis more than merely perceptible fuming.

- The articles to be treated are preferably previously heated ,to about600 degrees F. in order to obtain the best results. While cold metal maybe treated with satisfactory final results by this process, the timerequired is very great. When heated to the temperature indicated, thearticles can be rendered rust-proof in from ten .to forty minutes. Thearticles may be treated in the furnace wherein they are heated or theymay be placed in a special treating chamber.

The acid meta-phosphates are heated to a high temperature to produceabundant fumes which are acid in. character. This may be done in thetreating chamber or in an especially constructed furnace, the fumesbeing drawn into the treating chamber by means of a suction fan placedwhere most eflcctive. If desired, a jet of dry steam may be caused toenter the treating chamber to render the fumes more active in character.The duration of the treatment will depend upon the character of themetals treated and also upon the desired character of the coating.

It has been found that the mixing of about two per cent. of the acidmetaphosphates of molybdenum, strontium or ed to receive paint, enamel,lacquer and even other metals by electro-plating.

Volatile metals such as zinc may be mixed with the acid meta-phosphatesduring the time they are heated to produce the fumes,

and the action thereof seems to be the production of more even and densesurfaces having high resistance to the corroding effects of the elementsin the atmosphere.

The combination of molybdenum, tungsten or any of the metals of thethird,'fourth and fifth groups as stated above, with an excess ofmeta-phosphoric acid to form a paste is temporary and maybe partlybroken up at any time by the application of heat. These metals all havethe characteristic offreely entering into this combination. The fumesare produced by the decomposition of these acid salts, and are deliveredmore regularly than if the metaphosphoric acid is heated alone, probablyowing'to the mechanical carrying over of small particles of acid whenthe liquid boils.

I claim 1. A new and useful processconsisting in subjecting articles ofiron and steel to the action of fumes from acid meta-phosphates oftungsten, molybdenum or of any of the metals of the third, fourth andfifth groups, singly or in combination with each other.

2. A new and useful process consisting in subjecting articles of ironand steel to the action of steam mixed with the fumes from acidmeta-phosphates of tungsten molybdenum or of any of the metals of thetlnrd, fourth and fifth grou s.

3. A new and usefu process consisting in subjecting heated articles ofiron and steelto the action of fumes caused by heating acidmeta-phosphates of tungsten molybdenum or of any of the metals of ethird,

fourth and fifth groups.

, .4. A new and useful process consisting in meta-phosphates of ironmixed with a small percentage of acid meta-phosphate of molybdenum,strontium or tungsten. I

' 7 A newand useful process consisting in subjecting heated articles ofiron and steel to the action of fumes roduced by heating acidmeta-phosphates 0 iron to wlnch fumes a quantity of steam has beenadded.

8. A new and useful process consistingin subjecting articles of iron'andsteel to the action of fumes produced by heating acid meta-phosphates ofiron, to which fumes a quantity of steam has been added.

9. A new and useful process consisting in subjecting articles of ironand steel to the action of fumes produced byheating acid meta-phosphatesof iron and a. volatile metal.

10. A new and useful process consisting in subjectin articles of ironand steel to the action 0 fumes produced by heating acid meta-phosphatesof iron and zinc.

WALTER I. OESCHGER.

